'Carbon time bomb': climate crisis threatens to destroy Congo's peatlands

Congo’s peatlands are a huge carbon ‘ticking time bomb’ that could be triggered by the climate crisis, research has found.

Peatlands shifted from storing carbon to releasing it into the atmosphere when the climate became drier 5,000 years ago, the study showed, before reverting to accumulating carbon 2,000 years ago .

Scientists now fear that man-made global warming could tip the fragile system upside down again, accelerating the climate crisis.

The peatlands, which span the Democratic Republic of Congo and the Republic of Congo, are the largest in the tropics and cover 17 million hectares (42 million acres). They store a large amount of carbon – the equivalent of three years of global fossil fuel emissions. They are also threatened by logging and oil and gas development.

“We now know that these peatlands are very close to this tipping point where they could release billions of tonnes of carbon into the atmosphere,” said Professor Simon Lewis, from the University of Leeds, UK. Uni, and University College London, and lead author. of the study. “We don’t know exactly how far but we do know that over the past two decades droughts have been prolonged in the central Congo Basin.

“Our study provides a stark warning from the past. This is an important message for world leaders gathered at the COP27 climate talks. »

Professor Corneille Ewango from the University of Kisangani in the Democratic Republic of Congo, who led the peat sampling expeditions, said: “Peatlands are more vulnerable than we thought and everyone has to play their part. To protect them. Polluting countries must reduce their carbon emissions quickly.

The Minister of the Environment of the Republic of Congo, Arlette Soudan-Nonault, declared: “It is more than ever essential that rich and polluting countries commit themselves financially to the protection of our peatlands, our biodiversity and the populations local. If we are to prevent this gigantic reservoir of carbon from turning into a ticking time bomb, our partners must understand that this invaluable planetary ecosystem service cannot remain free forever.

The research was published in the journal Nature and used cores taken from peat layers to reconstruct the history of peatlands. The ratio of hydrogen isotopes in the wax indicated the amount of rain that fell as the leaves grew. The work showed that the drought lowered the water table, exposing the peat to air and decay.

“Our results indicate a positive feedback in the global carbon cycle – climate-induced drying in the central Congo Basin leads to the release of more peat carbon into the atmosphere,” the researchers concluded.

More research is needed to determine how much carbon was released during the previous dry period and how quickly, although it took at least decades or centuries, the researchers said. Dr Yannick Garcin, of the National Research Institute for Sustainable Development and lead author of the study, said: “This drought has caused a huge loss of peat, at least 2 meters. The drought has turned the bog into a huge carbon source.

Research published in September showed that five dangerous tipping points may have already been passed due to the 1.1C global warming caused by humanity to date, including the collapse of the Greenland Ice Sheet. and a key current in the North Atlantic. The study considered the Congo Basin as a potential tipping point, but found insufficient evidence.

“The new study confirms that Congo’s peatlands are vulnerable to climatic drying,” said Professor Tim Lenton, from the University of Exeter and a member of the team who undertook the September analysis. “For now, I would keep the Congo peat bog and rainforest on the ‘uncertain’ and ‘slow’ list of potential climate system tipping points, but it is clearly a carbon sink and a vital ecosystem that we should all seek to preserve.” Fires burning peat could cause carbon emissions much faster, he added.

Vanessa Nakate, a prominent Ugandan climate justice activist, said: “We are on the brink of [climate] disaster. The Congo Basin is one of the most underestimated resources on the planet. It is a beehive for biodiversity and a huge carbon sink. We must protect it. »